Reproduction: primary testicular failure: practice question

A Physiology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Physiology · Reproduction: primary testicular failure

Sample item

A tall 24-year-old man with small firm testes, gynaecomastia and azoospermia has a 47,XXY karyotype and a low serum testosterone. Which hormonal pattern is expected?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

C. Low testosterone with raised LH and FSH from loss of negative feedback

In Klinefelter syndrome the seminiferous tubules and Leydig cells are damaged, so testosterone and inhibin B are low. The anterior pituitary is intact and, released from feedback, secretes more LH and FSH, giving hypergonadotropic hypogonadism. Low testosterone with relatively high oestradiol also explains the gynaecomastia.

Option by option

  • A. Low testosterone with low LH and FSH from pituitary failure

    Low gonadotrophins with low testosterone is hypogonadotropic hypogonadism, as in Kallmann syndrome.

  • B. Normal testosterone with raised LH and low FSH

    Normal testosterone with a low FSH does not match tubular failure, where FSH is raised.

  • C. Low testosterone with raised LH and FSH from loss of negative feedback (correct)

    Testicular failure removes testosterone and inhibin feedback and so raises both gonadotrophins.

  • D. High testosterone with suppressed LH and FSH

    High testosterone with suppressed gonadotrophins is typical of an androgen-secreting tumour or exogenous androgen use.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this Physiology question

What is the answer to this Physiology question?

The best answer is C, Low testosterone with raised LH and FSH from loss of negative feedback. In Klinefelter syndrome the seminiferous tubules and Leydig cells are damaged, so testosterone and inhibin B are low.

Why is "Low testosterone with low LH and FSH from pituitary failure" not the answer?

Low gonadotrophins with low testosterone is hypogonadotropic hypogonadism, as in Kallmann syndrome.

Why is "Normal testosterone with raised LH and low FSH" not the answer?

Normal testosterone with a low FSH does not match tubular failure, where FSH is raised.

Why is "High testosterone with suppressed LH and FSH" not the answer?

High testosterone with suppressed gonadotrophins is typical of an androgen-secreting tumour or exogenous androgen use.

What concept does this question test?

It tests Reproduction: primary testicular failure in Physiology. The anterior pituitary is intact and, released from feedback, secretes more LH and FSH, giving hypergonadotropic hypogonadism. Low testosterone with relatively high oestradiol also explains the gynaecomastia.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Reproduction: primary testicular failure?

For each system, sketch the key graph (pressure–volume loop, oxygen dissociation curve, nephron handling) and explain it aloud. Then use the flashcards and the other Physiology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.